A pixel circuit of an organic light emitting diode (OLED) is a circuit that controls current flowing through the OLED by a driving transistor and is mainly used in a display device. A structure of the pixel circuit of the OLED generally includes an OLED and a plurality of driving transistors.
In the related art, the pixel circuit of the OLED generally includes a switching transistor, a driving transistor, a capacitor and an OLED. The driving transistor can convert a data voltage of a data signal terminal into a drive current for driving the OLED. The magnitude of the drive current is related to a threshold voltage (Vth) of the driving transistor.
However, if the Vth of the driving transistor is different between different pixel units or the Vth of the driving transistor drifts over time, the current of the OLED flowing through each pixel unit is different, so that homogeneity of display brightness of an OLED display panel is low and a display effect is poor.